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Leona Marshall Libby’s Interview

Manhattan Project Locations:

Leona Woods, later Leona Woods Marshall and Leona Marshall Libby, was 23 in 1942, the only woman present when Enrico Fermi’s nuclear pile at the University of Chicago went critical and into the history books. She moved to Hanford in 1944 with her husband, fellow physicist John Marshall. Marshall Libby was one of the few women scientists in the Manhattan Project and probably the most well known. Even so, during an interview she laughed off questions about what it was like to be so distinctive. She did mention DuPont had been thoughtful enough to provide her with a private bathroom at the reactor buildings.

Date of Interview:
September 12, 1986
Location of the Interview:


[At top is the edited version of the interview published by S. L. Sanger in Working on the Bomb: An Oral History of WWII Hanford, Portland State University, 1995.

For the full transcript that matches the audio of the interview, please scroll down.]

Book version:

I worked with John Wheeler and I helped solve the riddle of the Hanford xenon poisoning. Remember, this was the first big reactor in the world. Here were all these bigshots, lining the walls, to watch the startup. The operators were all coached. They had manuals. They had been through the routine X-Y-Z times. So here comes startup. You can see the water getting hot, the readings going up on the Brown recorders, you could hear it rushing in the tubes, you could see the control rods coming out and out and out. Later, something happened, and there was no more reactivity. The reactor went dead, just plain dead. People stood around and stared at each other. Wheeler had been at Oak Ridge, so he knew about the Oak Ridge reactor, which had showed signs of misbehavior, which could have been interpreted as poison, but you couldn’t prove it. At Hanford, we had the time period, the time it took for the reactor to go up to power, die and come back on. I would say Wheeler solved it, no doubt.

Before the xenon trouble, there was the problem of putting jackets on the fuel slugs. We walked around, and looked and walked around, we were sup-posed to figure it out. The guys who dipped the slugs in the molten flux solved it. They called it underwater canning. Well, nothing was going to work if the slugs didn’t work. One of the technicians, as I recall, solved the slug canning problem. I must say they never got enough credit. It was a clever person, whoever it was, and I hope he got a bonus but I doubt it.

We wanted to get out of Hanford as fast as we could but we couldn’t since we were babysitting the reactors. I remember John was on the night shift and I was on the afternoon. My mother was there to care for our child. For recre­ation we looked at the desert a little bit, but have you ever been to Hanford? Yes, Hanford was a factory, a plutonium factory. That was why it was built, exactly right.

Yes, I knew Szilard. He had a very special place in the world. He devel­oped a group of fresh Ph.Ds who formed a clique. They brought their minds to bear on problems that would become important after the war. Nobody else did that. Already, he had given over more or less the physics problems to Fermi and Wigner and concerned himself instead with these in part philo­sophical, but also exceedingly practical, questions. A really amazing man, really an amazing man. Fermi was very steady by comparison.

I think everyone was terrified that we were wrong (in our way of develop­ing the bomb) and the Germans were ahead of us. That was a persistent and ever-present fear, fed, of course, by the fact that our leaders knew those people in Germany. They went to school with them. Our leaders were terrified, and that terror fed to us. If the Germans had got it before we did, I don’t know what would have happened to the world. Something different. Germany led in the field of physics, in every respect, at the time war set in, when Hitler lowered the boom. It was a very frightening time.

I certainly do recall how I felt when the atomic bombs were used. My brother-in-law was captain of the first minesweeper scheduled into Sasebo Harbor. My brother was a Marine, with a flame thrower, on Okinawa. I’m sure these people would not have lasted in an invasion. It was pretty clear the war would continue, with half a million of our fighting men dead not to say how many Japanese. You know and I know that General (Curtis) LeMay firebombed Tokyo and nobody even mentions the slaughter that happened then. They think Nagasaki and Hiroshima were something compared to the firebombing.


I have no regrets. I think we did right, and we couldn’t have done it dif­ferently. Yeah, I know it has been suggested the second bomb, Nagasaki, was not necessary. The guys who cry on shoulders. When you are in a war, to the death, I don’t think you stand around and ask, “Is it right?”


Full transcript:

S. L. Sanger:  This is an interview 1986 with Leona Marshall Libby at her office on the UCLA campus in Los Angeles. Well one of the questions I have for you is, I understand that you are one of the few women in the project, is that right, physicists at least, the Manhattan Project?

Leona Marshall Libby:  Yes.

Sanger: And were you the only one at Hanford?

Libby:  Yes.

Sanger:  I mean physicists.

Libby:  Only woman.

Sanger:  Only woman. Well because I know that famous photograph at the University of Chicago, that you’re the only woman in it. 

Libby:  No that was after—

Sanger:  That was taken some time later, wasn’t it?

Libby:  Yes it was, but the point is it was the group that may—that was present when the reactor finally went.

Sanger:  This is kind of a digression I suppose, but I was curious if you had any particular—if anybody took note of the fact that you were a woman. Did you have any problems, I mean, or were you treated differently?

Libby:  That’s a dumb thing to say!

Sanger:  I know you mentioned there was a—you had your separate restroom at Hanford I guess. I was just curious, I mainly wanted to check that you were—

Libby:  The women—

Sanger:  The only woman at Hanford.

Libby:  Yes.

Sanger:  Except I suppose—

Libby:  Secretaries—

Sanger:  Secretaries and so on. I’ve got some of the background of that from John Marshall, the dates when you were there and I don’t have to go into that. One of the things we like to ask is, what is your recollection of Hanford, just as far as living there was concerned?

Libby:  We got out as fast as we could, but we couldn’t. We were babysitters. 

Sanger:  You were one of the reactor babysitters?

Libby:  Yes.

Sanger:  So you stayed until sometime after they went into production, didn’t you? Was your job similar to your husband’s?

Libby:  Yes, he was on one shift and I was on another.

Sanger:  So it was pretty much, you did the same thing.

Libby:  He was on the night shift, I was on the afternoon.

Sanger:  Oh. Well then how did you handle your—the child?

Libby:  My mother was there.

Sanger:  Oh, for the whole time?

Libby:  Sort of. 

Sanger: Now, you were working with John Wheeler, is that right?

Libby: Yes.

Sanger:  And you had a fairly important part in the Xenon poisoning riddle, figuring out what went wrong?

Libby:  Yes. 

Sanger:  Is that when you were working with Wheeler or with Fermi? He was there too?

Libby:  Well it was discovered—actually Johnny [Wheeler] discovered it. It was discovered the night of start-up. Remember, this was the first reactor in the world. And here were all these big shots like Bill Mackie and so on, coming in and lining the walls to watch the start-up. And operators were all coached, they had manuals, they’d been through the routine X, Y, Z times. 

So here comes start-up, and you could see the water getting hot, going through the brown recorders, you could hear it rushing in the tubes, and you could see the control rods coming out and out and out. 

And then something happened. They started to go back in, and they went in and in and in until there wasn’t any reactivity. The reactor was dead, just plain dead! Everybody stood around and stared at everybody. It was way after midnight, and so we drove back in the moonlight about 70, 80 miles to Richland. Enrico was driving the car. As long as he was there, I worked with him, and we argued about what caused it.

Sanger:  So you were there when it split down or quit?

Libby:  Yeah, and then Johnny took over, John Wheeler. Of course he was a senior guy, Johnny Wheeler. And besides, he had been at Oak Ridge and he knew about the Oak Ridge reactor, which is not a water cooler reactor, it was air-cooled, and it showed signs of misbehavior, which could have been interpreted as poison, but it wasn’t clear, couldn’t prove it. It’s just too low power. 

So they went over the various poisons, which of course he’d been over a lot of times to see what fitted, because we now had the period, the time to go up, and then it died at another time, then you sit and wait and it comes back on. So they had three times.

So what happened was Johnny had the operators pull the rods after about three or four hours and he saw it had reactivity. 

Sanger:  Well, Henry Newsome, you remember?

Libby:  Yeah.

Sanger:  He’s dead now. 

Libby:  Henry died?

Sanger:  I talked to his wife, that’s somebody I forgot to mention. 

Libby:  Oh dear.

Sanger:  In fact, I was at Duke when Alvin Weinberg gave the memorial lecture, so I talked to Weinberg. Yeah, I think he’s been dead for several, five or six years or so. 

Libby:  Always shakes me up.

Sanger:  And so then after you figured out—then you figured out what had —

Libby:  Well by morning, it was pretty well worked out so Enrico and I came back for the day shift, and saw what Johnny had done and it made sense. So I would say Wheeler solved it, without any doubt. 

Sanger:  Yeah, he went into that in some detail. Was that probably the most interesting scientific event in your experience at Hanford? 

Libby:  I think that before that there was a problem with putting jackets on the slugs. You heard about that.

Sanger:  Were you involved with that?

Libby:  Oh yeah. We walked around and looked and looked and walked around and we were supposed to have figured it out. And the very next day, the guys who dipped the slugs in the molten flux solved it, called it underwater candy.

Sanger:  How did it happen that you were mixed up with that?

Libby:  They got me into everything, and I take it very kindly.

Sanger:  Because that wasn’t particularly a problem with physics, was it?

Libby:  Well, nothing was going to work if those slugs didn’t work. I mean, the corrosion of all that water rushing through was just too powerful.

Sanger:  What’s your recollection of who, if anybody in particular, solved that problem? Or was it a group of people?

Libby:  Well it was the technicians. And they, I must say, didn’t get enough credit. 

Sanger:  The DuPont people—

Libby:  Only everybody worked for DuPont. I worked for DuPont. 

Sanger:  Yeah. I have heard that story about the slugs from a couple of DuPont people. And one of the fellas gave a guy named—I think his name was Swenson, some credit for it. He was the operator, the person who was—

Libby:  It’s hard to tell. It’s like getting somebody out of the machine shop. It’s about that level of training. It was a clever person who got no credit.

Sanger:  Yeah.

Libby: I hope he got a bonus, but I doubt it. 

Sanger: On that subject of DuPont, was there much friction between say the scientists like yourself and the DuPont engineers and technicians on this job. Do people work together pretty well as far as Hanford was concerned?

Libby: It wasn’t known to me, the friction; I think everyone was terrified.

Sanger:  Of what?

Libby: That we were wrong, and that the Germans were ahead of us. That was a persistent and ever present fear, fed of course by the fact that our leaders knew those people in Germany and had gone to school with them at every major university. So we were terrified.

Sanger: When you say you were afraid you were wrong, what do you mean?

Libby: They had gotten it before we did. I don’t know what would have happened to the world if something different.

Sanger: That’s one thing I was going to ask you about is, people have stressed the context of the time. Sometimes forgotten when people complain about nuclear weapons is that the Germans were incredible, monstrous fear, and that’s the reason that it was done.

Libby: They led then the civilized world of physics in every aspect at the time that the war set in, that Hitler lowered the boom. They led, not we. Very frightening time. 

Sanger:  Do you recall any sort of ferment at Hanford, or maybe you’d left by then, about the use of the bombs?

Libby: I think we fell between—I think it was midway, namely, as we were leaving Hanford, the ferment began at Chicago. But when we arrived at Chicago the classes were—people were starting to think about learning physics and chemistry. I remember most of that gang didn’t even have PhDs, they had come right out of graduate school. They are today’s professors, of course, and they had a lot of learning to do. So who was left to worry about it were Szilard, Wigner I’m pretty sure did worry, Compton, and people like that, who really didn’t have anything else to do except worry.

Sanger:  I understand that when the work was done and they turned their energies to concerns for the future I guess.

Libby:  Well, not the young ones, and the intermediate ones were teaching, but the ones of the rank, I said, didn’t have anything to do, so that’s what they did.

Sanger:  Was there a fairly large group of scientists at Hanford, or were most of the people engineers and technicians?

Libby:  See it was all designed—it was already [inaudible] design, and when we first got there they had a railroad engine on the banks of the Columbia, pouring water through the tubes to watch the corrosion, that had to do with the slugs. They built a lab for the slugs and they were building the reactors. What were they – B, D, F?

Sanger:  Yeah.

Libby:  It’s like getting a recipe.

Sanger:  So in other words, I mean, the population of scientists was not—physicists was not great at Hanford?

Libby:  No, but of very high quality. The best that DuPont had to offer. And with consulting from Fermi and Wigner and Compton.

Sanger:  And now Fermi came to Hanford several times?

Libby:  Yeah.

Sanger:  But did he stay very long?

Libby:  Maybe three or four weeks.

Sanger:  You had been close to him for quite some time, I mean since Chicago?

Libby:  Yes. 

Sanger:  Because I know—

Libby:  Well since they came—since the Manhattan Project came to Chicago. 

Sanger:  Your husband, or John Marshall had known him before?

Libby:  Right.

Sanger:  He told me the story about how he was chosen to be Szilard’s hands, and that’s how he got involved in this originally.

Libby:  Yeah.

Sanger:  Did you know Szilard?

Libby:  Oh yeah.

Sanger:  What was your impression of him?

Libby:  He had a very special place in the world. He developed a group of fresh PhD’s. They formed a clique, and brought their minds to bear on problems that would become important for after the war. And nobody else did that. And he already had more or less given over the physics problems to Fermi and Wigner, and concerned himself instead with these in part philosophical and also exceedingly practical questions. Really amazing man, really amazing man.

Sanger:  Very imaginative, I’ve guessed, from what I’ve heard.

Libby:  Different; yes.

Sanger:  I guess exasperating at times too?

Libby:  Well I think brilliant people frequently are; yes.

Sanger:  What about Fermi? Did he have any kind of mercurial personality? Was he steady or say like Szilard by comparison?

Libby:  Very steady. Doesn’t everybody say that?

Sanger:  Yeah, there’s some wonderful stories about him, and some of them are in your book. I don’t know if you want to go into that too much.

Since you were involved at Hanford, which made the plutonium for the Nagasaki bomb, I have been asking people if they—if at the time or now that they have a feeling that second bomb was necessary to end the war. What’s your feeling on that, or do you recall what you felt then?

Libby:  I certainly do. My brother-in-law was captain of the first bombs’ minesweeper scheduled into Sasabo harbor. My brother was a Marine, was a flamethrower on Okinawa. I’m sure these people wouldn’t have lasted. It’s pretty clear we would have had half a million of our fighting men dead, and not to say whom we would have killed of the Japanese. I mean, you know and I know that LeMay firebombed Tokyo. And nobody even mentions the slaughter that happened then, all these dead people. They think that Nagasaki and Hiroshima were something compared to firebombing Tokyo. They’re wrong. And then we gave them medals, we gave medals to LeMay, did you know that?

Sanger: Mm-hmm; yeah.

Libby:  So I have no regrets. In wartime, it was a desperate time. I think we did right and we couldn’t have done differently.

Sanger:  In hindsight some historians have suggested that maybe the second bomb wasn’t necessary.

Libby:  Yeah, I know. The guys who cry on shoulders.

Sanger:  They also say that no one knows for sure either at this late date.

Libby:  When you’re in a war to the death, I don’t think you stand around and say, “Is it right?” 

Sanger:  Did you ever, after the war was over, did you work on nuclear weapons related projects again?

Libby:  Not much. Mostly it was to push on to the high-energy particle physics. I’m trying to remember if there were one or two papers, which could have been interpreted as related to—I would say no, no I didn’t. 

But it wasn’t a conscious choice. It was rather opportunity and what was Enrico interested in. We were asking him, “Why do you want to know that?” “What do you want to know about high energy forces?” It shows what a dumbbell I was. Now young people are much smarter now than they used to be.

Sanger:  You asked him that, and what did he say?

Libby:  I think he probably just couldn’t believe his ears.

Sanger:  What about now? I mean, a person with your historical connection with the bomb, what are your views on nuclear weapons nowadays?

Libby:  You can’t stop it. How can you stop it? You’re going to tell a guy like [Muammar] Gaddafi, “Don’t buy that bomb from the Israelis,” or wherever you’re going to buy it? You can tell him, and he’s going to do—I mean you cannot stop the wheels. That’s my view. And again, the do-gooders and the crying on shoulders, these guys have got blue-eyed optimism that is not useful. What’d Johnny Marshall say?

Sanger:  Well, let’s see. I read over the interview with him. I think he said that—I’m not sure—I can’t remember for sure but I think it was something like, “It’s one of those things and perhaps there are too many nuclear weapons or if they were used it would be the end of the world probably, but it exists.”

Libby:  I don’t believe in ends of anything. 

Isn’t Johnny an interesting man?

Sanger:  Yeah, he is. Wonderful house.

Libby:  We built that together.

Sanger:  Oh did you?

Libby:  But what I mean is, as a person he doesn’t show the qualities, which have made him the fine physicist that he is. He’s reserved.

Sanger:  He is reserved. In fact, I thought he was quite low key and seemingly very relaxed.

Libby:  But if he says something, that’s right. 

Sanger:  You met him at Chicago?

Libby:  Yes. 

Sanger:  He was with Fermi by then, huh?

Libby:  Yes. 

Sanger:  As I said, your book is so complete that some of these questions are repetitive. 

When you were in Hanford, how did you relax? Everybody talks about hiking and that sort of thing. Was that the main way to get away from the work?

Libby:  Have you ever been to Hanford?

Sanger:  Yeah.

Libby:  Did you see any place to hike to?

Sanger:  Well, no. Wheeler talked a lot about walking.

Libby:  I don’t think he walked. I think he walked from the cafeteria to his office.

Sanger:  What did you do for fun? Anything?

Libby:  Well yeah we looked at the desert a little bit. You know my stories about that. 

Sanger: In the book.

Libby:  It’s much nicer now than it used to be, because it’s watered again. By the time that we got there, the orchards had all dried up, and all that was left is the detritus from when the glaciers went out.

Sanger:  Sandstorms.

Libby:  Oh yeah, sandstorms.

Sanger:  Have you been back?

Libby:  Yes, once. 

Sanger:  Professor [Herbert] Anderson said that he in his view he agreed that Hanford was mainly a plutonium factory. That was its role. Is that your perspective?

Libby:  Yes it’s a factory, that’s why it was built; exactly right. And I think Herb built the first aspect of it there in Hanford. He came and made an air-cooled reactor very much like the Oak Ridge reactor.

Sanger:  For the test materials?

Libby:  Yes.

Sanger:  I guess it’s still there; I assume it is.

Libby:  Yes.

Sanger:  The B Reactor of course is there, it’s some national engineering landmark now. I’ve visited it a couple of times.

Libby:  Yes.

Sanger:  It’s still a godforsaken area.

Libby:  Yes.

Sanger:  Let’s see, well I guess that’s enough. What are you doing now mostly?

Libby:  Right now, just looking at some papers I should get published. It’s always a fight with the editors if it’s new. Right now I’m working on you know what are quasi stellar objects? They’re supposed to be farther away than anything else that there is that we can see. They’ve got a bunch of lines, which nobody knows what those are. I’m originally a spectroscopist, and I’m trying to figure out what can those lines be. I use the National Bureau Standards and work on this since Billy died. Somehow by some miracle, these papers I’ve written most recently do get published, they do, but it’s more difficult than getting a book published.

Sanger:  Are you teaching too?

Libby:  No, I just stopped in January. I was every quarter getting $65,000 for the kiddos, every two quarters, and keeping them all alive, but I think I’ve done my share.

Sanger:  Would you have graduate students working with you?

Libby:  I did.

Sanger:  Not now?

Libby:  I stopped in January. 

Sanger:  What they what, in geophysics?

Libby:  No, these were in engineering.

Sanger:  Oh, that’s the department you’re in officially, huh, is engineering?

Libby:  Right now. Environmental science.

Sanger:  Yeah?

Libby:  Yeah.

Sanger:  You’re technically part of that department?

Libby:  Yes.

Copyright 1989 S. L. Sanger. This transcript may not be quoted, reproduced, or redistributed in whole or in part by any means except with the written permission of S. L. Sanger.